CN117026842A - Double-splicing coupling installation method for arch ribs of fully assembled steel tube arch bridge - Google Patents

Abstract

The invention provides a double-splicing coupling installation method for a fully assembled steel pipe arch bridge arch rib, which belongs to the technical field of arch bridge steel structure construction and comprises the following steps: step 1, string tube lengthening; step 2, truss sheet installation; step 3, installing arch rib sections; step 4, installing arch rib flanges; step 5, installing a wind brace; step 6, digital simulation assembly; and 7, scanning and checking. The invention adopts the horizontal and vertical double-splicing coupling installation method of the arch rib, and is matched with the three-dimensional laser scanning digital simulation splicing technology, thereby improving the splicing efficiency and precision and enabling the arch rib to be installed at high altitude smoothly; when the member processed by the technology is lifted at high altitude, the member is restored and installed according to the vertical splicing state, the number of wind stay installation is 2 per day, compared with the welding for 4-5 days/each wind stay installation, the key line occupation of the wind stay installation is effectively avoided, the time of the arch rib large cantilever is greatly reduced, and the structural risk is effectively reduced.

Description

Double-splicing coupling installation method for arch ribs of fully assembled steel tube arch bridge

Technical Field

The invention relates to the technical field of arch bridge steel structure construction, in particular to a double-splicing coupling installation method for an arch rib of a fully assembled steel pipe arch bridge.

Background

In recent years, with the high-speed development of the domestic road bridge industry, the steel structure arch bridge obtains unprecedented application space, but with the wide application of the steel structure arch bridge, the complete technical system is not yet researched in the manufacturing technology of the steel pipe arch bridge, and especially the large-span assembled steel pipe arch bridge technology has a special lack of experience. Because the large-span steel pipe arch bridge has a large section and a complex structure, and the field installation working condition is more complex, the common practice of the steel structure arch bridge is to split or make small-section semi-finished products to be transported to the field to be spliced into large sections, and then to hoist the large sections. The traditional small-component loose-splice installation process is often limited by site working conditions and geographical environments, site construction workload is large, site construction quality and construction precision are not effectively guaranteed, the large-section installation process is limited by installation site assembly sites, transportation and hoisting equipment, and processing cost is high. The fully-assembled bolted arch rib mainly adopts a cantilever assembly mode, high-altitude installation and adjustment measures are very limited, so that the arch rib installation accuracy is difficult to control, the field installation workload is large and complicated, in the process of building a large-span steel pipe arch, improvement and innovation are carried out on the basis of the traditional process, and the arch rib is subjected to double-splicing process and digital analog assembly technology to realize the high-accuracy installation of the fully-bolted assembled arch rib, so that the fully-assembled steel pipe arch bridge arch rib double-splicing coupling installation method is provided.

Disclosure of Invention

The invention aims to provide a double-splicing coupling installation method for arch ribs of a fully assembled steel pipe arch bridge, which solves the technical problems of difficult control of arch rib installation accuracy, large field installation workload and complexity caused by limited existing high-altitude installation and adjustment measures. The arch rib of the invention realizes the high-precision installation of the full-bolting assembled arch rib by combining a double-splicing process with a digital analog splicing technology, ensures the smooth high-altitude installation, realizes the rapid closure of the arch rib and reduces the cantilever splicing safety risk.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the double-splicing coupling installation method of the full-assembled steel pipe arch bridge arch rib comprises the following steps:

step 1, string tube lengthening, drawing a ground sample line according to a tube section line shape, erecting a string tube jig, mounting the tube section on the string tube jig, aligning a tube section datum line with the ground sample line, carrying out positioning welding on the tube section, transferring to a rotary jig for welding, and returning to the string tube jig for checking the line shape to obtain a string tube;

step 2, installing truss sheets, namely, according to stress-free manufacturing lines, drawing truss sheet ground sample lines, erecting truss sheet horizontal splicing jig frames, adjusting arch rib joints and lines after string pipes are mounted with the tyres, positioning and installing I-shaped web members and box-shaped web members with the tyres after string pipes are mounted with the tyres in sequence and checked without errors, and then installing upright column joints on the string pipes to obtain truss sheets;

step 3, installing arch rib segments, measuring levelness of truss sheets by using a high-precision level after the truss sheets are manufactured, ensuring that the measured deviation is less than 2mm, symmetrically positioning and installing transverse connecting rods on lower truss sheets, positioning and installing upper truss sheets and the transverse connecting rods to obtain arch rib segments, leaving a public segment on a jig frame, and finishing the next round of installation according to the steps;

and 4, installing a rib flange, determining the projection position of the flange plate according to the stress-free manufacturing line shape after the rib segments are installed, fixing the plate surface by adopting a positioning tool, respectively welding stiffening ribs at one end of the flange plate on the chord tube and the plate surface, and reserving welding seams of the plate surface and the stiffening ribs at the other end, wherein the reserved gap is 0.5-1.5cm.

And 5, installing the air stay, namely after string pipes and air stay tire lines are lofted in the vertical splicing site, installing the vertical splicing tire frame, turning over two sections of arch rib sections by 90 degrees by using a gantry crane, installing the two sections of arch rib sections on the vertical splicing tire frame, positioning and welding the air stay between the two sections of arch rib sections to obtain an arch rib, and leaving a public section on the tire frame, thereby completing the next round of installation according to the steps.

Step 6, digital simulation assembly, namely after the vertical assembly is completed, scanning the vertical assembly line shape of the arch rib by using a three-dimensional laser scanner to perform simulation assembly, fitting an actual theoretical model and a stress-free BIM model, and judging three-dimensional precision;

and 7, scanning and checking, namely reserving the public segment on a jig frame, and adjusting the gesture of the public segment according to the requirement of the vertical alignment line, wherein in the adjustment process, a three-dimensional laser scanner is adopted to judge whether the gesture meets the requirement or not so as to ensure the three-dimensional gesture of 'N+1', and realize the precision transmission among different rounds.

Further, in the step 1, the chord tube joint length is replaced by a straight bending mode, the length of the tube section is smaller than 3m, the chord height is controlled within 5mm, the welding line is a roller tire frame started on a rotary tire frame, and an automatic submerged arc welding machine is used for welding the circumferential welding line of the tube section after the positioning welding.

Further, in step 2, after the i-web member and the box-web member are mounted on the truss horizontal splicing jig frame according to the ground pattern line and positioned, the box-web member is vertically welded between the chord tubes through the node plates, the i-web member is obliquely welded between the chord tubes through the node plates, the chord tubes and the front corner weld of the node plates are subjected to positioning welding and welding deformation correction, the chord tubes and the back corner weld of the node plates are subjected to positioning welding and welding deformation correction by turning over, and then the upright post joints and the chord tube corner weld are subjected to positioning welding and welding deformation correction.

Further, in step 3, the mounting steps of the transverse link are as follows: the welding deformation is corrected by carrying out positioning welding on the chord tube fillet weld of the transverse connecting rod and the lower truss sheet, then checking the levelness, then installing the upper truss sheet in a hanging hammer line mode, controlling the arc linearity of the arch rib, adopting the truss sheet horizontal splicing jig frame to carry out fixed limit, measuring the levelness of the upper truss sheet to ensure the verticality of the section after 90 degrees of overturning, and carrying out positioning welding on the chord tube and the transverse connecting rod fillet weld of the upper truss sheet and correcting the welding deformation after all linear accuracy is checked to meet the requirement.

Further, in step 3, before each round of horizontal splicing is performed on the tire, a three-dimensional laser scanner is adopted to scan the horizontal splicing three-dimensional gesture, the three-dimensional gesture of the common section in the next round is determined through simulation pre-splicing, so that the accuracy continuation of the horizontal splicing line shape is ensured, and meanwhile, an actual scanning model is subjected to model according to the vertical splicing gesture, so that the vertical splicing section line shape is determined.

Further, in step 5, the jig frame is assembled immediately and adopts the square pier as main load-carrying structure, and square pier top surface sets up crescent regulation dental lamina elevation deviation and is less than 1mm, and square pier plane size sets up to 800 x 800mm, sets up the buttress of 800mm altogether, 1200mm, 1400mm three kinds of high is used for adjusting the main arch rib line form, and the place of assembling in advance arranges the measuring bench in the suitable position, and single group jig frame comprises 12 square piers, adopts the total powerstation to carry out unwrapping wire location when the festival section is assembled to use rag bolt to make the buttress fixed, use the spirit level to measure after the buttress is fixed and confirm dental lamina height.

Further, in step 5, after the rib segment is put on the tire, the longitudinal joint position, the rib verticality, the side bending and the upper chord elevation line shape are adjusted, the deviation between the line shape and the ground pattern line of each member of the rib is controlled within the standard requirement, and after the rib segment is put on the tire, the joint measurement inspection is carried out on the whole round to control the rib segment verticality, the vertical splicing elevation line shape and the diagonal line yield value.

Further, in step 5, the wind brace includes an X brace, an upper horizontal brace, an upper diagonal brace, a lower horizontal brace, and a lower diagonal brace, where the X brace, the upper horizontal brace, and the lower horizontal brace are respectively installed at one ends between two arch rib segments, and the upper horizontal brace and the lower horizontal brace are respectively installed at the upper and lower sides of the X brace, the upper diagonal brace and the lower diagonal brace are respectively installed at the other ends between two arch rib segments, and one end of the upper diagonal brace is installed on the upper horizontal brace, and one end of the lower diagonal brace is installed on the lower horizontal brace.

And after the three-dimensional accuracy is inspected to be qualified, opening the disc surface of the arch rib flange disc to clean foreign matters, then temporarily fastening, symmetrically and uniformly welding the arch rib flange stiffening plate at the other end with the disc surface, welding and cooling to complete assembly, setting measurement observation points at the positions of the chord tube axis and the waist line, and measuring three-dimensional attitude data by using a high-accuracy total station.

Further, in step 7, before the next wheel segment is mounted, according to the three-dimensional attitude of the common segment, according to the digital simulation assembly technology, the elevation of each tire frame of the next round is accurately judged, and control is performed according to the secondary elevation, so that the efficiency of tire alignment adjustment on the segment is improved, and after the adjustment of the common segment is completed, the steps are repeated to complete the installation of the subsequent round.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1. the invention adopts horizontal and vertical double-splicing coupling installation of arch ribs, the arch ribs are processed according to stress-free lines through horizontal coupling assembly, then steel members turn over and are coupled and assembled according to a bridge forming state, wind bracing is installed under the bridge forming state, and after a wind bracing joint plate is welded, the precision of wind bracing high-bolt joints is improved, so that the smooth assembly of a high-altitude cantilever of a steel structure is ensured.

2. The flange is processed by adopting a high-precision milling machine processing technology, the temporary bolt is tightly attached to the flange surface after the flange is processed by adopting a disc surface machine, one end of the flange is welded with a string pipe, after the vertical splicing line is accepted, the flange stiffening plate is welded with the string pipe at the other end, and finally the flange is opened to ensure 100% attachment of the overhead cantilever splicing flange.

3. The invention utilizes three-dimensional laser scanning digital detection to simulate assembly, reduces the field implementation engineering quantity, saves the steel structure processing and field installation resource consumption, is more beneficial to the control of steel structure processing and installation precision, reduces the repeated input of resources, improves the resource utilization rate and reduces the influence on the environment.

4. The invention adopts a digital simulation assembly technology to change the quality detection and precision control mode of the traditional steel structure processing, utilizes software to carry out simulation adjustment and assembly, simulates possible problems of subsequent assembly, verifies the feasibility of subsequent installation, ensures the subsequent installation precision and improves the construction efficiency; the simulation software is utilized to fit the actually measured scanning model with the target scanning model and the BIM theoretical model, the machining precision of the steel structure is analyzed in a three-dimensional mode, the machining quality of the steel structure is improved, meanwhile, the problem of accurate continuous of the N+1 pre-splicing line is solved through computer model simulation, the quick lofting technology of the N+1 vertical splicing jig is realized, and the vertical splicing time is saved.

5. The invention adopts the horizontal and vertical double-splicing coupling installation method of the arch rib, and is matched with the three-dimensional laser scanning digital simulation splicing technology, thereby improving the splicing efficiency and precision and enabling the arch rib to be installed at high altitude smoothly; when the member processed by the technology is lifted at high altitude, the member is restored and installed according to the vertical splicing state, the number of wind stay installation is 2 per day, compared with the welding for 4-5 days/each wind stay installation, the key line occupation of the wind stay installation is effectively avoided, the time of the arch rib large cantilever is greatly reduced, and the structural risk is effectively reduced.

Drawings

FIG. 1 is a schematic illustration of a chord tube extension of the present invention;

FIG. 2 is a schematic view of the installation of truss sheets and rib segments of the present invention;

FIG. 3 is a schematic view of the installation of the wind brace of the present invention;

FIG. 4 is a schematic view of the installation of the rib flange of the present invention;

fig. 5 is a schematic view of the installation of the rib of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below by referring to the accompanying drawings and by illustrating preferred embodiments. It should be noted, however, that many of the details set forth in the description are merely provided to provide a thorough understanding of one or more aspects of the invention, and that these aspects of the invention may be practiced without these specific details.

The double-splicing coupling installation method of the full-assembled steel pipe arch bridge arch rib comprises the following steps:

step 1, as shown in fig. 1, a string pipe is lengthened, a ground sample line is drawn according to a line shape of a tube section, a string pipe jig is erected, the tube section is mounted on the string pipe jig, a tube section datum line is aligned with the ground sample line, the tube section is transferred to a rotary jig for welding after being subjected to positioning welding, and then the string pipe is obtained after returning to the string pipe jig for checking the line shape; the chord tube joint length adopts a mode of directly replacing the curve, the length of the tube section is less than 3m, the chord height is controlled within 5mm, the welding seam is a roller tire frame started on a rotary tire frame, and an automatic submerged arc welding machine is used for welding the circumferential welding seam on the tube section after the positioning welding.

Step 2, as shown in fig. 2, installing truss sheets, drawing truss sheet ground sample lines according to stress-free manufacturing lines, erecting truss sheet horizontal splicing jig frames, adjusting arch rib joints and lines after string pipes are mounted with the tyres, positioning and installing I-shaped web members and box-shaped web members with the tyres after string pipes are mounted with the tyres in sequence and checked without errors, and then installing upright joints on the string pipes to obtain truss sheets; after the I-shaped web member and the box-shaped web member are mounted on the truss piece horizontal splicing jig frame according to a ground pattern line for positioning, the box-shaped web member is vertically welded between the chord tubes through the node plates, the I-shaped web member is obliquely welded between the chord tubes through the node plates, the chord tubes are subjected to positioning welding and welding deformation correction with the front angle welding seam of the node plates, the chord tubes are subjected to positioning welding and welding deformation correction with the back angle welding seam of the node plates in a turn-over manner, and then the upright post joints are subjected to positioning welding and welding deformation correction with the chord tube angle welding seam. In the welding process, the welding shrinkage variable is considered in advance, the node plate is drilled in advance according to the design requirement, and after the joint position high bolt hole is welded, matching drilling is carried out according to the position of the node plate so as to ensure the high bolt through hole rate.

Step 3, as shown in fig. 2, after the rib segments are installed, measuring the levelness of the rib segments by using a high-precision level gauge, ensuring that the deviation of each measurement is less than 2mm, after transverse connecting rods are symmetrically positioned and installed on the lower layer of the rib segments, positioning and welding the transverse connecting rods and the angle welding joints of the chord tubes of the lower layer of the rib segments, correcting welding deformation, checking levelness, installing the upper layer of the rib segments by means of a hammer line, controlling the radian line shape of the rib segments, fixing and limiting by adopting a rib horizontal splicing jig frame, ensuring the verticality of the rib segments after 90 degrees of overturning by measuring the levelness of the upper layer of the rib segments, positioning and welding the angle welding joints of the chord tubes and the transverse connecting rods of the upper layer of the rib segments and correcting welding deformation after all linear precision is checked to meet the requirement, and leaving the public segments on the jig frame, and completing the next round of installation according to the steps; before each round of horizontal splicing and tire taking, a three-dimensional laser scanner is adopted to scan the horizontal splicing three-dimensional gesture, the three-dimensional gesture of the common section in the next round is determined through simulation pre-splicing, so that the accuracy continuation of the horizontal splicing line shape is ensured, and meanwhile, an actual scanning model is subjected to model according to the vertical splicing gesture, so that the vertical splicing section line shape is determined. The verticality of the section after 90 degrees of overturning is ensured by measuring the level of the truss sheet at the upper layer.

And 4, installing a rib flange, determining the projection position of the flange plate according to the stress-free manufacturing line shape after the rib segments are installed, fixing the plate surface by adopting a positioning tool, respectively welding stiffening ribs at one end of the flange plate on the chord tube and the plate surface, and reserving welding seams of the plate surface and the stiffening ribs at the other end, wherein the reserved gap is 0.5-1.5cm.

And 5, installing the air stay, namely after the string pipe and the air stay tire line are lofted in the vertical splicing site, installing the vertical splicing tire frame, turning over the two arch rib sections by 90 degrees by using the gantry crane, installing the two arch rib sections on the vertical splicing tire frame, positioning and welding the air stay between the two arch rib sections to obtain an arch rib, and reserving the public section on the tire frame, thereby completing the next round of installation according to the steps. The vertical splicing jig frame adopts a square pier as a main bearing structure, the elevation deviation of a crescent adjusting tooth plate is smaller than 1mm, the plane size of the square pier is 800 multiplied by 800mm, three heights of the square pier, namely 800mm, 1200mm and 1400mm, are arranged for adjusting the shape of a main arch rib, a measuring table is arranged at a proper position in a pre-splicing site, a single group of jig frames consists of 12 square piers, a total station is adopted for paying off and positioning during segment splicing, the piers are fixed by using foundation bolts, a leveling instrument is used for measuring and determining the height of the tooth plate after the piers are fixed, the vertical splicing jig frame is used for vertically splicing arch ribs, the top surface of the piers of the jig frame is leveled, and the jig frames are arranged on the same straight line and are arranged near a stress point of the structure as much as possible; after the arch rib section is put on the tire, the position of a longitudinal joint, the verticality of the arch rib, the side bending and the line shape of the upper chord elevation are adjusted, the deviation between the line shape and the ground pattern line of each member of the arch rib is controlled within the standard requirement, and after the tire is put on the arch rib section, joint measurement inspection is carried out on the whole round to control the verticality of the arch rib section, the line shape of the vertical splicing elevation and the diagonal line production value; the wind props including X prop, go up the horizontal brace, go up the bracing, lower the horizontal brace and lower the bracing, X prop, go up the horizontal brace and install the one end between two sections arch rib sections respectively with lower the horizontal brace, and go up the horizontal brace and install the upper and lower both sides at X respectively with lower horizontal brace, go up the bracing and install the other end between two sections arch rib sections respectively with lower the bracing, and go up the one end of bracing and install on last horizontal brace, the one end of lower bracing is installed on lower horizontal brace. The method comprises the steps of temporarily connecting an X brace with a node plate and a web plate in advance, firstly installing a lower horizontal brace and a lower diagonal brace to a temporary air brace jig frame, backing and welding the lower node plate, then installing an upper node plate, fixing a horse plate, welding an upper node plate, a lower node plate, a rib penetration welding seam, positioning and welding the web plate on the other side of the node position, opening the lower horizontal brace, the lower diagonal brace and the node plate when the node plate is welded, enabling the node plate to deform freely in the welding process, preventing the rib deformation, and after the positioning and welding of the horizontal brace and the lower diagonal brace are completed, integrally positioning and installing the X brace, firstly arranging a supporting stiffening plate below the parallel node plate, then positioning and welding the lower node plate and the upper node plate, secondly completing the welding of the X brace node plate, and after the X brace is installed, connecting a long rod with a short rod through field matching drilling, and welding the upper horizontal brace and the upper diagonal brace welding seam according to a lower horizontal brace and lower diagonal brace welding method.

Step 6, as shown in fig. 5, digital simulation assembling, after the vertical assembling is completed, scanning the vertical assembling line shape of the arch rib by using a three-dimensional laser scanner to perform simulation assembling, fitting an actual theoretical model and a stress-free BIM model, and judging the three-dimensional precision; and after the three-dimensional accuracy is inspected to be qualified, opening the disc surface of the arch rib flange disc to clean foreign matters, then temporarily fastening, symmetrically and uniformly welding the arch rib flange stiffening plate at the other end with the disc surface, welding and cooling to complete assembly, setting measurement observation points at the positions of the chord tube axis and the waist line, and measuring three-dimensional attitude data by using a high-accuracy total station.

Step 7, scanning and checking, namely reserving the public segment on a jig frame, and adjusting the gesture of the public segment according to the requirement of the vertical alignment line, wherein in the adjustment process, a three-dimensional laser scanner is adopted to judge whether the gesture meets the requirement or not so as to ensure the three-dimensional gesture of 'N+1', and realize the precision transmission among different rounds; before the next wheel segment is mounted on the tire, according to the three-dimensional gesture of the public segment, according to the digital simulation assembly technology, accurately judging elevation of each tire frame of the next round, and controlling according to the secondary elevation, thereby improving the efficiency of linear adjustment of the tire on the segment, and repeating the steps after the adjustment of the public segment is completed to complete the subsequent round of installation. The arch rib is divided into a plurality of sections, the continuous sections are continuously matched and installed, and the common sections are arranged to realize the precision continuation among different rounds; the assembly turns are comprehensively determined mainly according to requirements of sites, field devices, construction periods and the like; the arch rib is firstly assembled through horizontal splicing coupling, the arch rib is processed according to a stress-free line shape, then the steel member is turned over and assembled according to a bridge-forming state coupling, the wind brace is installed in a matched mode under the bridge-forming state, the wind brace joint plates are welded, the precision of the wind brace high-bolt joint is improved, and the smooth assembly of the steel structure high-altitude cantilever is ensured.

Example 1

Drawing a ground sample line according to a cylindrical shell section line shape, erecting a long chord tube splicing jig, installing a first cylindrical shell section on the chord tube splicing jig, aligning a datum line on the first cylindrical shell section with the ground sample line, tightly jacking and fixing the first cylindrical shell section by using a long chord tube splicing jig template, installing a second cylindrical shell section on the long chord tube splicing jig, aligning a tetrad line on the second cylindrical shell section with the first cylindrical shell section, ensuring that longitudinal seams are staggered by 90 degrees, aligning the datum line on the second cylindrical shell section with the ground sample line, tightly jacking and fixing the second cylindrical shell section by using the long chord tube splicing jig template, positioning and welding the nodes of the first cylindrical shell section and the second cylindrical shell section, repeating the steps, sequentially splicing to obtain a long chord tube splicing, transferring the long chord tube splicing jig to a rotary jig, starting a roller jig, using an automatic submerged arc welding machine to apply circumferential weld, and returning to the long chord tube splicing jig after welding is completed; the chord tube joint length adopts a straight bending replacing mode, the length of a tube section is smaller than 3m, the chord height is controlled within 5mm, and the allowable deviation of the chord tube joint length is shown in table 1:

table 1 string tube length control index unit: mm (mm)

Firstly, manufacturing a line shape according to stress-free, drawing a ground sample line, erecting a truss piece horizontal splicing jig frame, then installing a first string pipe on the truss piece horizontal splicing jig frame, aligning a datum line on the first string pipe with the ground sample line, tightly jacking and fixing the first string pipe by utilizing a truss piece horizontal splicing jig frame template, adjusting an arch rib joint and the line shape, installing a second string pipe on the truss piece horizontal splicing jig frame, aligning a datum line on the second string pipe with the ground sample line, and tightly jacking and fixing the second string pipe by utilizing the truss piece horizontal splicing jig frame template; after the positioning of the chord tube upper tire is checked, an I-shaped web member and a box-shaped web member are vertically installed between a first chord tube and a second chord tube through a node plate, the I-shaped web member and the box-shaped web member are installed on a truss piece horizontal splicing tire frame according to a ground sample line for positioning, then the chord tube and a node plate front angle welding seam are subjected to positioning welding and welding deformation correction, the chord tube and a web member node plate back angle welding seam are subjected to positioning welding and welding deformation correction by turning over, then upright post joints are installed on the first chord tube and the second chord tube according to a line shape, and the upright post joints and the chord tube angle welding seam are subjected to positioning welding and welding deformation correction; in the welding process, the welding shrinkage variable is considered in advance, the node plate is drilled in advance according to the design requirement, and after the joint position high bolt hole is welded, matching drilling is carried out according to the position of the node plate so as to ensure the high bolt through hole rate.

After the truss sheet is manufactured, measuring the levelness of the truss sheet by using a high-precision level gauge, ensuring that the measured deviation is smaller than 2mm, symmetrically installing transverse connecting rods on chord tubes of the truss sheet at the lower layer after the accuracy of the truss sheet at the lower layer meets the requirement, respectively positioning and welding the transverse connecting rods between the chord tubes, the I-shaped web members and the box-shaped web members of the truss sheet at the upper layer, positioning and welding deformation of the transverse connecting rods, the I-shaped web members and the box-shaped web members, checking the levelness, installing the truss sheet at the upper layer, controlling the arc linearity of arch ribs by a hammer line mode, fixing and limiting by adopting a truss sheet horizontal splicing jig frame, and ensuring the verticality after the sections are turned by 90 degrees by measuring the levelness of the truss sheet at the upper layer, positioning and welding the chord tubes and the angle welding joints of the transverse connecting rods and correcting the welding deformation after all the linear accuracy meets the requirement. After the previous round of horizontal splicing matching is completed, the common section is left on the truss piece horizontal splicing jig frame, the posture is adjusted according to the arch rib processing drawing, then the next round of matching manufacturing is completed by referring to the steps, the three-dimensional laser scanner is adopted to scan the horizontal splicing three-dimensional posture before each round of horizontal splicing, the three-dimensional posture of the common section in the next round is determined through simulation pre-splicing, so that the accuracy continuation of the horizontal splicing line shape is ensured, and meanwhile, the actual scanning model is modeled according to the vertical splicing posture, so that the vertical splicing section line shape is determined. The horizontal splicing coupling matching manufacturing method comprises the steps of accurately lofting horizontal unstressed lines of arch ribs in advance by adopting a tire line method, placing chord tubes and web members on a horizontal splicing tire frame, aligning the ground patterns, controlling the positions of two ends of a section, temporarily fixing the sections, and then applying the sections as web member nodes; the segments are matched according to the integral line shape under the limit of the field, and the line shape continuity is realized through the common matching segment.

After the arch rib sections are finished, the projection position of the flange plate is determined according to the stress-free manufacturing line shape, the plate surface is fixed by adopting a positioning tool, then stiffening ribs at one end of the flange plate are welded on the chord tube and the plate surface respectively, and welding seams of the plate surface and the stiffening ribs are reserved at the other end, wherein the reserved gap is 0.5-1.5cm.

After string pipes and air bracing tire line lofting are carried out in the vertical splicing field, a vertical splicing tire frame is installed, two sections of arch rib sections are turned over by 90 degrees by using a gantry crane and then are installed on the vertical splicing tire frame, an arch rib is obtained by positioning and welding air bracing between the two sections of arch rib sections, a public section is reserved on the tire frame, and the next round of installation is completed according to the steps. The vertical splicing jig frame adopts a square pier as a main bearing structure, the elevation deviation of a crescent adjusting tooth plate is smaller than 1mm, the plane size of the square pier is 800 multiplied by 800mm, three heights of the square pier, namely 800mm, 1200mm and 1400mm, are arranged for adjusting the shape of a main arch rib, a measuring table is arranged at a proper position in a pre-splicing site, a single group of jig frames consists of 12 square piers, a total station is adopted for paying off and positioning during segment splicing, the piers are fixed by using foundation bolts, a leveling instrument is used for measuring and determining the height of the tooth plate after the piers are fixed, the vertical splicing jig frame is used for vertically splicing arch ribs, the top surface of the piers of the jig frame is leveled, and the jig frames are arranged on the same straight line and are arranged near a stress point of the structure as much as possible; after the horizontal splicing of the arch ribs is completed, 2 100-ton gantry cranes are adopted to hoist the upper tire to complete preliminary positioning, and main arch rib sections are adjusted according to the position of a ground pattern line and measurement data, so that the positioning of the arch ribs meets the standard requirements; the inspection items are: the side line of the inner side of the arch rib is bent sideways (the lower chord is rechecked with the ground sample line of the inner side, the upper chord is measured by a total station), the length of the arch rib (the ground sample line of the port position of the arch rib is measured), the verticality of the arch rib (the lower chord pipe is measured by a plumb bob), the elevation of the arch rib (the difference from the design linearity) and the diagonal line of the central section of the inner arch pipe are different; the wind brace comprises an X brace, an upper horizontal brace, an upper inclined brace, a lower horizontal brace and a lower inclined brace, wherein the X brace is temporarily connected with a node plate and a web plate in advance, the lower horizontal brace and the lower inclined brace are firstly installed to a wind brace temporary jig frame and the lower node plate is subjected to backing welding, then the node plate is installed and fixed by a horse plate, the upper and lower node plates and an arch rib are welded through a welding seam, then the web plate at the other side of the node position is positioned and welded, when the node plate is welded, the lower horizontal brace and the lower inclined brace are opened with the node plate, so that the node plate can be deformed freely in the welding process, the arch rib is prevented from deforming, the X brace is integrally positioned and installed after the positioning welding of the horizontal brace and the lower inclined brace is completed, the stiffening plate is firstly arranged under the parallel node plate, then the lower node plate and the upper node plate are welded in a positioning manner, then the welding of the X brace node plate is completed, and after the X brace is installed, a long rod and a short rod are connected in a matching manner, and the upper horizontal brace and the upper inclined brace welding seam are welded according to the positioning and lower inclined brace welding method.

After the vertical assembly is completed, a three-dimensional laser scanner is used for scanning the vertical assembly line shape of the arch rib to carry out simulation assembly, an actual theoretical model and a BIM model in a stress-free state are fitted, and three-dimensional precision of the model is judged; and after the three-dimensional precision is inspected to be qualified, opening the disc surface of the arch rib flange disc to clean foreign matters, then carrying out temporary fastening, symmetrically and uniformly welding the arch rib flange stiffening plate at the other end with the disc surface, after welding, repairing and coating welded and damaged parts, reliably protecting a welding port of a construction site, avoiding paint pollution and rust, finishing assembly after welding and cooling, setting measurement observation points at the positions of a chord tube axis and a waist line, and measuring three-dimensional posture data by using a high-precision total station. Checking and accepting the vertical splicing quality, mainly checking the verticality (measuring the inner side of an arch rib), the elevation (linear difference with design), the side bending of the arch rib, the length of the arch rib, the diagonal difference of an inner arch pipe and the like; after the arch rib is vertically spliced and accepted, marking measuring points on waist lines and axes which are 1-2m away from the upper and lower chord pipe orifices, wherein the arch rib vertically splicing control indexes are shown in table 2:

TABLE 2 control index unit mm for vertical splicing of ribs

The common section is reserved on a jig frame, the posture of the common section is adjusted according to the requirement of the vertical alignment, and in the adjustment process, a three-dimensional laser scanner is adopted to judge whether the posture meets the requirement or not so as to ensure the three-dimensional posture of 'N+1', and the precision transmission among different rounds is realized; before the next wheel segment is mounted on the tire, according to the three-dimensional gesture of the public segment, according to the digital simulation assembly technology, accurately judging elevation of each tire frame of the next round, and controlling according to the secondary elevation, thereby improving the efficiency of linear adjustment of the tire on the segment, and repeating the steps after the adjustment of the public segment is completed to complete the subsequent round of installation.

Example 2

(1) In-situ data acquisition

Firstly, setting a coordinate system on a steel structure assembly site, reasonably setting chessboard paper according to the steel structure assembly site, measuring the center coordinates of the chessboard paper by using a high-precision total station, and assigning values for scanning coordinates of a model. A LeP 50 three-dimensional laser scanner is adopted to obtain a holographic three-dimensional model of the arch rib section, a Leica total station scanner MS60 is adopted to supplement a local high-precision scanning model, and a TS series high-precision measuring robot is adopted to establish a construction coordinate system of the holographic scanning model.

Before the scanning work starts, firstly, the site is required to be subjected to the surveying work, the number of the stations and the placement positions of the target balls for scanning are determined mainly according to the spatial distribution, the shape and other characteristics of the steel pipes and the site conditions, the data acquisition is ensured to be completed by using the minimum number of the stations, and the error in splicing is reduced. The target balls are placed so that there are at least 3 common target balls for scanning between adjacent sites for point cloud registration of different sites. And (3) placing target paper at the waist line of the steel pipe arch rib to control the subsequent pre-assembled reference surface. When the three-dimensional laser scanner collects field data of the steel pipe component, no shielding exists between the scanning site and the measured object, and the distance between the scanning site and the measured object is in a proper range (the distance is determined according to the height of the instrument), so that the measured object can be scanned to the maximum extent.

(2) Preliminary processing of data

And (3) importing the acquired data of each site into a closed computer software system (a system carried by the three-dimensional laser scanner), and forming complete three-dimensional data after a series of operations such as point cloud denoising, point cloud splicing, point cloud coloring and the like. The point cloud is spliced mainly by connecting target balls shared by adjacent sites, the point clouds are spliced together by utilizing a least square algorithm, and the splicing precision is processed by an internal adjustment algorithm. The integrity of the data and the quality of the point cloud can be timely known in the preprocessing process, and incomplete data points are directly supplemented or rescanned if the point cloud quality is problematic. Because the scanner adopts 360-degree horizontal and 320-degree vertical rotation scanning, the scanned data has more redundancy, and only needed parts are selected as far as possible for facilitating the subsequent data processing

(3) Establishing a high-precision model

The three-dimensional holographic scanning model with the error within 2mm is obtained in a large-span bridge by utilizing a sub-millimeter-level point cloud registration target and a long-distance point cloud accurate registration algorithm, and a foundation is laid for the application of three-dimensional precision control of a steel structure, rapid pre-assembly of the steel structure, high-precision installation simulation of the steel structure and the like.

(4) Three-dimensional accuracy inspection

According to the arch rib line shape with the preset lifting value, software such as Revit or sknchUP is adopted in advance to build a three-dimensional high-precision model, and the BIM model is used as a basis for checking the machining precision of the steel structure; by adopting Geomagic quality auxiliary detection software, the product is rapidly detected by comparing the actually scanned point cloud model with the three-dimensional design model, and the detection result is displayed by a visual and easily understood chromatographic graph; the main monitoring items include the manufacturing precision of arch rib members, the linear precision of arch ribs, the tapping precision of bolts and the like.

(5) Digital analog assembly

"n+1" vertical spelling quick adjustment based on digital pre-assembling

Step 1: before the entity is spliced vertically, scanning the segments to be spliced vertically one by one;

step 2: the scanned arch rib segments are subjected to digital n+1 vertical spelling, the theoretical vertical spelling is taken as a target, the scanned arch rib model is subjected to virtual pre-assembly, and the optimal posture of each arch rib is searched, so that the deviation between the actual vertical spelling of the arch rib and the theoretical linear spelling is minimum;

step 3: giving out a correction suggestion of fire correction at an overrun position of the arch rib, and finishing correction of manufacturing errors of the arch rib section before entity erection;

step 4: giving out a lofting instruction on the top surface of the jig frame, giving out a target posture of each arch rib section when the entity is vertically spliced, and realizing the rapid adjustment of the arch rib sections when the entity is vertically spliced;

the application of the technology optimizes the process flow of the entity vertical spelling, reduces the workload during the entity vertical spelling, obviously improves the progress and the precision of the entity vertical spelling, realizes the 'one-step in place' of the entity vertical spelling, and predicts and saves the arch rib vertical spelling adjustment time by 2 days in each round.

a. Fast fine tuning of 'n+1' vertical spelling public segment based on digital pre-assembly

Step 1: accurately scanning to obtain a final arch rib segment model of the previous round;

step 2: transforming the common segment model of the previous round into a new round coordinate system by adopting coordinate system transformation among the vertical spelling rounds, and taking the common segment model of the previous round as a target gesture of fine adjustment of the common segment of the new round;

step 3: the public segment is initially placed on a new-round jig frame, and the initial three-dimensional gesture is scanned to obtain a current situation model;

step 4: comparing the deviation between the target model and the current model, and providing 6-degree-of-freedom fine adjustment instructions for the public segment adjustment by adopting a self-grinding three-dimensional attitude fine adjustment technology;

step 5: according to the three-dimensional fine adjustment instruction, a high-precision total station is adopted to cooperate with on-site fine adjustment measures, so that high-precision posture restoration of the public section is realized;

step 6: and finally judging whether the public segment is positioned with high precision or not after the three-dimensional gesture of the public segment is subjected to the repeated scanning adjustment.

By the application of the technology, the resetting precision of the public segment is improved, the problem that the line shape is out of control after the arch rib is hoisted to the public segment is solved, the fine adjustment speed of the public segment is greatly improved, and 50% of the working procedure time is expected to be saved.

N+1 entity vertical spliced arch rib linear digital test collection

After the entity of a round is vertically spliced, the actual vertical spliced line shape when the round is not spliced is subjected to three-dimensional scanning, three-dimensional deviation comparison is carried out between the actual vertical spliced line shape and the theoretical vertical spliced line shape, digital acceptance is carried out, the actual vertical spliced line shape is mastered, and the actual vertical spliced line shape is used as a target line shape standard for arch rib diagonal-draw buckling and hanging installation.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (10)

1. The double-splicing coupling installation method for the arch ribs of the fully assembled steel pipe arch bridge is characterized by comprising the following steps of: the method comprises the following steps:

step 1, string tube lengthening, drawing a ground sample line according to a tube section line shape, erecting a string tube jig, mounting the tube section on the string tube jig, aligning a tube section datum line with the ground sample line, carrying out positioning welding on the tube section, transferring to a rotary jig for welding, and returning to the string tube jig for checking the line shape to obtain a string tube;

step 2, installing truss sheets, namely, according to stress-free manufacturing lines, drawing truss sheet ground sample lines, erecting truss sheet horizontal splicing jig frames, adjusting arch rib joints and lines after string pipes are mounted with the tyres, positioning and installing I-shaped web members and box-shaped web members with the tyres after string pipes are mounted with the tyres in sequence and checked without errors, and then installing upright column joints on the string pipes to obtain truss sheets;

step 3, installing arch rib segments, measuring levelness of truss sheets by using a high-precision level after the truss sheets are manufactured, ensuring that the measured deviation is less than 2mm, symmetrically positioning and installing transverse connecting rods on lower truss sheets, positioning and installing upper truss sheets and the transverse connecting rods to obtain arch rib segments, leaving a public segment on a jig frame, and finishing the next round of installation according to the steps;

and 4, installing a rib flange, determining the projection position of the flange plate according to the stress-free manufacturing line shape after the rib segments are installed, fixing the plate surface by adopting a positioning tool, respectively welding stiffening ribs at one end of the flange plate on the chord tube and the plate surface, and reserving welding seams of the plate surface and the stiffening ribs at the other end, wherein the reserved gap is 0.5-1.5cm.

And 5, installing the air stay, namely after string pipes and air stay tire lines are lofted in the vertical splicing site, installing the vertical splicing tire frame, turning over two sections of arch rib sections by 90 degrees by using a gantry crane, installing the two sections of arch rib sections on the vertical splicing tire frame, positioning and welding the air stay between the two sections of arch rib sections to obtain an arch rib, and leaving a public section on the tire frame, thereby completing the next round of installation according to the steps.

Step 6, digital simulation assembly, namely after the vertical assembly is completed, scanning the vertical assembly line shape of the arch rib by using a three-dimensional laser scanner to perform simulation assembly, fitting an actual theoretical model and a stress-free BIM model, and judging three-dimensional precision;

and 7, scanning and checking, namely reserving the public segment on a jig frame, and adjusting the gesture of the public segment according to the requirement of the vertical alignment line, wherein in the adjustment process, a three-dimensional laser scanner is adopted to judge whether the gesture meets the requirement or not so as to ensure the three-dimensional gesture of 'N+1', and realize the precision transmission among different rounds.

2. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in the step 1, the chord tube joint length is replaced by a straight bending mode, the length of the tube section is smaller than 3m, the chord height is controlled within 5mm, the welding seam is formed by starting a roller tire frame on a rotary tire frame, and an automatic submerged arc welding machine is used for welding the circumferential welding seam of the tube section after the positioning welding.

3. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in step 2, after the I-shaped web member and the box-shaped web member are installed on the truss piece horizontal splicing jig frame according to a ground pattern line to be positioned, the box-shaped web member is vertically welded between chord tubes through a node plate, the I-shaped web member is obliquely welded between the chord tubes through the node plate, the chord tubes are subjected to positioning welding and correcting welding deformation with the front-face angle welding seam of the node plate, the chord tubes are subjected to positioning welding and correcting welding deformation with the back-face angle welding seam of the node plate by turning over, and then the upright post joint is subjected to positioning welding and correcting welding deformation with the chord tube angle welding seam.

4. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in the step 3, the mounting steps of the transverse connecting rod are as follows: the welding deformation is corrected by carrying out positioning welding on the chord tube fillet weld of the transverse connecting rod and the lower truss sheet, then checking the levelness, then installing the upper truss sheet in a hanging hammer line mode, controlling the arc linearity of the arch rib, adopting the truss sheet horizontal splicing jig frame to carry out fixed limit, measuring the levelness of the upper truss sheet to ensure the verticality of the section after 90 degrees of overturning, and carrying out positioning welding on the chord tube and the transverse connecting rod fillet weld of the upper truss sheet and correcting the welding deformation after all linear accuracy is checked to meet the requirement.

5. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in the step 3, before each round of horizontal splicing is performed on the tire, a three-dimensional laser scanner is adopted to scan the horizontal splicing three-dimensional gesture, the three-dimensional gesture of the common section in the next round is determined through simulation pre-splicing, so that the accuracy continuation of the horizontal splicing line shape is ensured, and meanwhile, an actual scanning model is subjected to model according to the vertical splicing gesture, so that the vertical splicing section line shape is determined.

6. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in step 5, the vertical splicing jig frame adopts a square pier as a main bearing structure, the crescent adjusting tooth plate elevation deviation is smaller than 1mm, the square pier plane size is 800×800mm, three high piers of 800mm, 1200mm and 1400mm are arranged in total to adjust the main arch rib shape, the pre-splicing site is provided with measuring tables at proper positions, the single-group jig frame is composed of 12 square piers, paying-off positioning is carried out by adopting a total station during segment splicing, the piers are fixed by using foundation bolts, and the tooth plate height is measured and determined by using a level after the piers are fixed.

7. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in step 5, after the arch rib section is put on the tire, the longitudinal joint position, the arch rib verticality, the side bending and the upper chord elevation line shape are adjusted, the deviation between each member line shape of the arch rib and the ground pattern line is controlled within the standard requirement, and after the arch rib section is put on the tire, the joint measurement inspection is carried out on the whole round to control the arch rib section verticality, the vertical splicing elevation line shape and the diagonal line production value.

8. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in step 5, the wind brace comprises an X brace, an upper horizontal brace, an upper diagonal brace, a lower horizontal brace and a lower diagonal brace, wherein the X brace, the upper horizontal brace and the lower horizontal brace are respectively arranged at one ends between two sections of arch rib sections, the upper horizontal brace and the lower horizontal brace are respectively arranged at the upper side and the lower side of the X brace, the upper diagonal brace and the lower diagonal brace are respectively arranged at the other ends between two sections of arch rib sections, one end of the upper diagonal brace is arranged on the upper horizontal brace, and one end of the lower diagonal brace is arranged on the lower horizontal brace.

9. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in the step 6, after the three-dimensional accuracy is checked to be qualified, opening the disc surface of the arch rib flange plate to clean foreign matters, then carrying out temporary fastening, symmetrically and uniformly welding the arch rib flange stiffening plate at the other end and the disc surface, completing assembly after welding and cooling, setting measurement observation points at the positions of the chord tube axis and the waist line, and measuring three-dimensional attitude data by using a high-accuracy total station.

10. The method for double-splicing and coupling installation of the ribs of the fully assembled steel pipe arch bridge according to claim 1, which is characterized in that: in step 7, before the next wheel segment is mounted on the tire, according to the three-dimensional gesture of the common segment, according to the digital simulation assembly technology, accurately judging the elevation of each tire frame of the next round, and controlling according to the elevation, thereby improving the efficiency of tire alignment adjustment of the segment, and repeating the steps after the adjustment of the common segment is completed to complete the installation of the subsequent round.